Reverting-test circuit for telephone systems



M. B. STAZAK. REVEBTING TEST CIRCUIT FOR TELEPHONE SYSTEMS. APPLICATIONFILED APR-27. 1914.

1,357,303, Patented Nov. 2, 1920.

2 2755555. 51/522252 Jz/Zz'afiasZfl 52525.4.

UNITED STATES PATENT OFFICE.

MICEIAEL B. STAZAK, OF CHICAGO, ILLINOIS, ASSIGNOR- TO KELLOGGSV/ITGHBOARD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OFILLINOIS.

REVERTING-TEST CIRCUIT FOR, TELEPHONE SYSTEMS.

Specification of Letters Patent.

Patented Nov. 2, 1920.

Application filed April 2'7, 1914. Serial No. 834,638.

1 '0 all whom "it may concern:

Be it known that 1, MICHAEL B. STAZAK, a citizen oi: the United Statesat America, residing in Chicago, county of Cook, and State of Illinois,have invented certain new and useful Improvements in Reverting-T estCircuits or Telephone Systems, of which the following is aspecification.

My invention relates to telephone systems and has to do moreparticularly with a reverting busy test by which the operator receives adistinctive busy signal when a test is being made at a jack multiplyconnected with the jack in which the answering plug has been inserted,an object being to provide an improved and simplified circuitarrangement which is positive in operation.

.vfly invention is illustrated in connection with an operators cordcircuit which is arranged for automatically cutting in the operator stelephone with the cord circuit when an answering plug is inserted intoa jack of a calling line, and for automatically disconnecting saidoperators telephone when the connection is completed by the insertion ofthe calling plug into a multiple jack of the called line. My inventionmay also be used with an operators cord circuit which is arranged formanually connecting the operators telephone with the cord circuit by theactuation oi a listening hey, the reverting tone test operating as whenused in connection with a cord circuit as described above, but I do notwish to be limited to the specific circuit arrangements illustrated as lcontemplate using said test in connecti on with. other cord circuits.

For a more complete understanding oi my invention reference may be hadto the accompanying drawing in wh1ch-- Figure 1 illustrates thereverting busy test used in connection with a cord circuit which isprovided with automatic listening.

2 illustrates a cord circuit similar to Fig. l but with a listening keybridged across the cord conductors for manually connecting the operatorstelephone.

Referring now more in detail to the system which embodies my inventionas illustrated in Fig. 1, it comprises a calling substation A connectedby the line limbs L with a line circuit B comprising a line relay LB, acutoff relay CO, line signal 1 and multiple jacks J. I have shown partyline terminals 1), E and F connectedto the line L for party lineservice.

The cord circuit 0 comprises an answering plug r and a calling plug Pcondensers 2 and 3 being interposed in the tip and sleeve conductorsconnecting the plugs and P The answering end of the COICl CIICUIlJcomprises a tip answering supervisory relay TA and a sleeve answeringsupervisory relay SA, the two relays controlling the answeringsupervisory signal 4c. The sleeve supervisory relay SA has contacts 12-,i l actuated upon insertion of the answering plug into the answeringjack for connecting the operators telephone with the cprd circuit. Thecalling end of the cord circuit C comprises a tipcalling supervisoryrelay TC and a sleeve calling supervisor relay SC, the two relayscontrolling the su pervisory signal The sleeve calling supervisory relaySC has contacts 10, 21 actuated upon the insertion of the calling plug Pinto a jack of the called line for auto matically disconnecting theoperators set from the cord circuit. A party line key BK is providedwhich, when any one of the four key plungers is depressed, connects anyone of the four ringing generators G, (P, r or G which is associatedwith the called substation, for signaling the said substation.

To the right of the drawing 1 illustrate a substation A similar to thatillustrated at substation A, and being connected by line limbs L to aline circuit B 'similar to the line circuit l3 and bearing the samereference numerals but having the suflix prime. 1 also show party lineterminals D E and F The reverting busy test circuit T'l com prises acomparatively high resistance reverting test relay RT, common to anopera tors position, which is actuated whenever the operator inserts ananswering plug into an answering jack. A test relay T is also providedwhich is actuated whenthe operator tests a multiple jack of any busyline but which is effective only when testing a jack of a calling line.

When aparty calls for another party on the same line and the operatortests, relay i energizes and due to the shunting effect of thecomparatively low resistance of the circuit including its winding andresistance 18, relay RT de'elnergizes, and therefore relay RT beingdeenergized and relay T energized, the special tone is connected incircuit with the third winding of the induction coil and thus throughthe operators receiver. The high resistance of relay RT also'preventsrelays RT and SA from loclr ing up in series through contacts 10, 12.

When a busy line different than the calling line is tested, althoughrelay T is en ergized, it is not effective because relay RT remainsenergized and only the ordinary busy cliclr is received by the operator.

In practice I have iiound that when operating on twenty-four volts thefollowing sistances give a successful operation. Relays TA, SA, TC andbi 100 ohms. Relay RT, 3100 ohms, relay T, 300 ohms and coils 18 and 20,50 and 300 ohms respectively. Relay Lit, 1000 ohms and relay GO, 500ohms. These values are 'iven for purpose of illustration and it is to beunderstood that they may be varied and still give satisfactory results.

Assuming now that a subscriber at su station A wishes to converse withanother subscriber, say at substation E for instance located on the sameparty line with A, the subscriber at A removes his receiver from theswitch-hook causingth energization of the relay L of the line circuit Bwhich at tracts its armature to close its alternate contact to light theline lamp 1. The operator inresponse to signal 1,. inserts an answeringplug P into the jack 5 of the called line. Relay SA of cord circuit Cand relay Ci) of line circuit B are energized in series from batterythrough relay SA, the sleeve con tacts of the plug P and jack J throughthe winding of relay CO to ground. The relay C0 operates and opensthe'circuit of the line relay LR, deenergizing the said relay LR andeii'acing the signal 1. The relay TA of cord circuit C also operatesfrom battery through the relay SA, sleeve contacts of the plug and jackJ, one line conductor of the line L, through substation A,'the otherline conductor of the line limbs L,tip contacts of jack J and plug Pthrough relay TA to ground. Relay TA energizes opening its normalcontact to prevent the signal l from lighting.

The high resistance reverting test relay RT of the tone test circuit TTis also 0perated from battery through the relay SA, normal contact 1O,conductor 11, alternate contact 12, conductor 13, through relay RT toground, the said relay ET energizing. The relay SA was energized, aswill be remembered, When the answering plug P was inserted into the jackJ and said relay closed its alternate contacts 12 and 1a to connect theoperators telephone O.

The operator having received the number from the calling subscriber,tests a multiple jack of the called line to, determine its idle or busycondition perhaps not knowing that the called subscriber E is located onthe same party line with'calhng subscr1ber A.

The operator in testing places the tip of the plug P against the sleeveof a multiple jack of the wanted substation E in the usual manner. Thesleeve of the jack being at a battery potential above ground which isextended from battery through relay SA of said circuit C over the sleeveconductor of the cord circuit, the relay T is energizedfroin battery atthe sleeve of the tested ack, the tip of the plug P normal contact15,'test conductor 16, winding of relay T to ground, said relay closingits alternate contact 17. The high resistance relay RT thus is shuntedby the low resistance circuit including resistance 18 and relay T, whichshunt can be traced from round at relay T through low resistance 18 andwinding of relay T, test conductor 16, normal contact 15, tip of plug Psleeve of the multiple jack, sleeve conductor of the cord circuit C,normal contactlt), alternate contact 12, conductor 13, to relay'RT. Therelay 1 1T therefore deenergizes and closes its normal contact 19 toconnect the reverting test tone which may be traced from ground throughthe secondary winding of coil 9, imper ance 20, normal contact1,alternate contact 17, through the third winding or" operatorsinduction coil to ground, the tone being induced into the secondary oithe operators induction coil and through the circuit including her headreceiver. T place the i111: pedance 20 in circuit with the revertingtone test to reduce the tone so that the operator will not receive aharsh tone in her head receiver.

1 This special tone indicates to the operator that she has tested amultiple jack which is associated with the jack in which the an sweringplug is inserted. The operator then notifies the calling subscriber atsubstation A to replace his receiver upon its switch-hook so that shemay ring the caller for subscriber The operator will then insert thecalling plug P into a'jack or" the said line which in this case would bethe jack J, after having removed the answering plug P. SC is thereforeenergized closing circuit for lamp 5. The operator will then signal thecalled-for subscriber on the party line by depressing the proper ringinghey. Upon both subscribersremoving their receivers the substations AandE are ready for conversation. Upon replacing their receivers theusual'disconnect signal is given and the op erator Withdraws the plug.

Assuming now that the subscriber at substation A wishes to converse witha subscriber at substation A the operation of this circuit is the sameas previously described,

the relay C0 of: the line circuit B, the relays SA and TA oi the cordcircuit C and the high resistance relay RT of the tone test circuit TToperate as before described, the operators set U being'automaticallycon- The relay nected to the cord circuit so that the operator mayascertain the wants of the calling subscriber. She then takes the plug Ptests the multiple jack J of the called line as to its idle or busycondition. If the line is busy there will be a battery potential uponthe sleeve of the multiple jack J from another cord circuit, saidbattery energizin the test relay T of the tone test circuit T'l, but asthe high resistance reverting test relay RT energizes in every case whenthe operator plugs into a calling line, the tone test is not put incircuit by reason of the contact of relay RT moving to its alternateposition but the operator receives the customary click in her headreceiver notifying her that substation A is in use. If idle, she insertsthe plug P into the multiple 'ack J The cut-off relay CO and relay S ofthe cord circuit C operate in series. The contacts 10 and 21 of therelay SC assume their alternate position automatically dis connectingthe operators set 0 from the cord circuit C. This interrupts the circuitfor the high resistance relay RT. of the tone test circuit TT the saidrelay deenergizing. The contact 15 of the relay SC opens its normalcontact interrupting the circuit of the relay T, the said relay SCclosing its alternate contact 22 and completing the continuity of thetip conductor. of the cord circuit G. The operator then depresses theproper ringing plunger connecting the proper generator to the tip sideof the line to ring the called for subscriber. The supervisory signal 5is lighted upon the closing of the alternate contact 22, the signal 5remaining lighted until the called-for subscriber answers when the relayT C operates to open the circuit of the signal 5.

Upon termination of conversation the subscribers at substations A and Areplace their receivers upon their respective switchhooks which actcauses the deenergization of relays TA and TC and closes circuit for thesignals 4 and 5, the said supervisory lamps 4c and 5 lighting andnotifying the operator that the subscribers at substations A and A havereplaced their receivers. The operator then takes down the connectiondeenergizing the relays SA and SC and effacing the signals 4 and 5.

In Fig. 2 I have illustrated an operators cord circuit C similar to theone illustrated in Fig. 1 withapparatus similar and bearing the samereference numerals but with suffixes added. The answering end of thecord circuit C comprises the relays TA and Sr the relay SA being withoutcontacts for automatically connecting the operators set. The calling endof the cord circuit 0 comprises the relays TC and SC the relay SC beingwithout contacts for automatically disconnecting the operators set. InFig. 2 I show a listening key IK bridged across the conductors of thecord circuit C which, when actuated, connects the operators set with thecord circuit C The tone test circuit TT as illustrated in Fig. 1performs the same function when operating in connection with Fig. 2 asin connection with Fig. l. I show the conductors which connect theoperators telephone extending from the listening key LK and also thetest conductor from the test contact of relay S0 The high resistancerelay HT is operated, when the operator throws her listening key afteran answering plug has been inserted into an answering jack, from batterythrough the winding of the relay SA the alternate contact 23 of thelistening key LK, conductor 2%, through the winding of the relay RT toground. The reverting tone test circuit operates the same when used inconnection with cord circuit C illustrated in Fig. 2 as when used inconnection with cord circuit of Fig. 1, the only material diiferencebeing that in Fig. 1 the operators set is connected automatically and inFig. 2 it is connected manually by the use of the operators key.

Having described my invention what I claim as new and desire to secureby United States Letters Patent is:

1. A telephone system comprising a calling telephone line, multiplejacks therefor, a cord circuit having an answering terminal connected toone of said jacks, an operators telephone, a reverting test relay forsaid cord energized responsive to connection of said operators telephoneto the cord, a test relay connected to the calling terminal of the cordenergized responsive to. the connection of the calling terminal toanother one of said jacks, such connection being also eifective todeenergize said first relay, and a test tone connected to said operatorstelephone responsive to deenergization of the reverting test relay andenergization of the test relay.

2. A telephone system comprising a calling telephone line, multiplejacks therefor, a cord circuit having an answering terminal connected toone of said jacks and tip and sleeve conductors connecting the answeringand calling terminals thereof, a revertingtest relay, circuitconnections for energizing and connecting said relay to the answeringsleeve conducton a-test relay energized responsive to the application ofthe calling terminal of the .cord to another one of said jacks, suchapplication also being effective to cause deenergizatio'n of thereverting test relay, and a test tone connected to said operatorstelephone responsive to the last said operations of the relays.

3. A telephone system comprising a telephone line, multiple jackstherefor, acord circuit, reverting test and test relays for the 7 forenergizing the reverting test relay, means responsive. to a test of saidline for deenergizing said reverting test relay and energizing said testrelay, and a test tone connected to said operators telephone responsiveto the last said operation of said relays.

a. telephone system comprising a calling line, multiple jacks therefor,a cord circuit having its answering end connected to one of said jacks,an operators telephone a reverting test relay, means for energizing saidrelay and connecting it to the answering terminal of the cord, a testrelay connected to the calling terminal of the cord, means 7 wherebywhen the calling terminal is applied to another of said jacks in testingsaid line said test relay is energized and the reverting test relaydeenergized, and circuit connections controlled through normal contactsof the reverting test relay and alternate contacts of the test relay forapplying a test tone to said operators telephone.

5. A telephone system comprising telephone lines, multiple jackstherefor, a cord circuit, an 'operators telephone, a reverting testrelay operated each time a call is answered, a test relay operated eachtime a busy called line is tested, ineans'whereby when a calling line istestedasacalled line the reverting test relay is deenergized, and a testtone connected to the operators tele-- phone responsive to suchdeenergization of the reverting test relay and a testing energizationofthe test relay. i

6. A telephone system comprising a telephone line, multiple jackstherefor, a cord circuit, an operators telephone, a high resistancereverting test relay, means for gizing said relay and connecting it tothe answering terminal of the cord in answering a call from said line, atest relay connected to the calling terminal of the cord, means forenergizing said test relay when testing said calling line as a calledline, a low resistance path including the winding of said test relay forshunting said reverting test relay to cause its deenergizationresponsive to said test, and a test tone applied to said operatorstelephone responsive to said energization of-the test relay anddeenergizatmn of the reverting test relay. 7

7. A telephone system comprising a telephone line, multiple ackstherefor, cord circuit provided with a pair of two-conductor terminals,an operators telephone adapted to be automatically connected to anddisconnected from said cord circuit, a revertive tone test'relay, manualmeans for connecting one terminal of said cord circuit to said telephoneline whereby said operators telephone and said revertive tone test relayare connected to said cord circuit, and means responsive to the applicaion of the other of said terminals to one of said multiple jacks forcausing said relay to apply a test tone to said operators telephone.

A telephone system comprising a telephone line, multiple jacks therefor,a link circuit providedwith a revertive tone test relay, meansresponsiveto the connection of the answering terminal of said link circuit to oneof said jacks for energizing said relay, means whereby when the callingterminal of said link circuit is applied to another of said multiplejacks said relay is deenergized and operates to connect a-test tone tosaid operators telephone. 7

9. A telephone system including a calling telephone line provided withmultiple jacks, a link circuit provided with ter ls, a revertive tonetest relay for said circuit, automatic means responsive to theconnection of one of said terminals to one of said jacks for energizingsaid relay, manual means for testing said line as a calledline byapplying the other of said terminals to another of said jacks wherebysaid relay is deenergized to connect a test tone to said operatorstelephone.

10. A telephone system comprising a telephone line, multiple jackstherefor, a cord circuit, a pair of relays for the cord circuit, anoperators telephone, means controlled by the operator when connectingher telephone in answering a call from said line. for energizing one ofsaid relays, means responsive to a test of said line forde'e'nergizingsaid re ay and for energizing the second of said relays, and a test toneconnected to said operators telephone responsive to the last saidoperation of said relaysi 11. A telephone system comprising telephonelines, multiple aclis therefor, a cord circuit, an operators telephone,a. revertive test relayoperated whena call is answered, a test relayoperated when a busy called line is tested, means whereby when a callingline is tested as a called line the revertive test relay isde'elnergized, and a test tone connected to the operators telephoneresponsive to suclrdeenergization of said revertive test relay and atestingenergization of the test relay.

A telephone system comprising a telephone line, multiple jacks therefor,a cord circuit provided with a pair of two-com ductor terminals, anoperators telephone,a

'evertive tone test circuit having normally open and a normally'closedcontact, means nsive to the connection of one of said ie to said linefor opening the normally closed contact, and means'responsive to a testby the other of said terminals of one of said multiple jacks for closingthe normally open contact and for causing the said first means to returnto normal whereby the test tone is operatively connected to saidoperators telephone, N

13. A telephone system comprising a tele phone line, multiple jackstherefor, .a cord circuit provided with a pair of terminals, anoperatofls telephone associated with said cord circuit, a revertive tonetest circuit provided with a normally open and a normally closedcontact, means responsive to the connection of one or said terminals toone of said multiple jacks for opening the normally closed contact, andmeans responsive to a test by the o her or said terminals of another ofsaid jacks for causing; the said normally open contacts to be closed andthe said normally closed contacts to be returned to normal whereby atone test is connected to said operators telephone.

let. A telephone system including a telephone line provided withmultiple jacks, a link circuit provided with a pair of terminals, anoperators telephone, a revertive tone test relay for said link circuit,means responsive to a connection of one or" said terminals to one 01'said jacks "for energizing said relay, means responsive to a connectionof the other otsaid terminals to another of said jacks for deenergizingsaid relay, and a busy tone generator for applying a tone to saidoperators telephone responsive to said deenergization of said relay.

15. A telephone system includingsubscribers telephone lines, a pluralityof link circuits for interconnecting said lines, an operators telephonecommon to said link circuits, a pair of relays associated with saidoperators telephone, a tone test de vice, a circuit for one of saidrelays adapted to be closed when the answering terminal of one of saidlink circuits is connected to a calling: one of said lines, a circuitfor the other of said relays adapted to be closed when the callingterminal of said link circuit is connected to another terminal of saidline, and contacts controlled by said relays for connecting said tonetest device to said operators telephone.

16. A telephone system including telephone lines, a plurality of linkcircuits for interconnecting said lines, an operators telephone commonto said link circuits, a pair of relays associated with said operatorstelephone, a tone generator, and means controlled by said relays forconnecting said tone generator to said operators telephone when theanswering terminal of one of said link circuits is connected to one ofsaid lines and the calling terminal or" said link circuit is used totest the said line.

17. A telephone system including a subscribers telephone line, aplurality of operators link circuits, operators telephone and aplurality of relays common to said link circuits, a tone test device,means for connecting one terminal of one of said link circuits to saidline, and means controlled by said relays for operatively connectingsaid tone test device to said operators telephone when the otherterminal of said link circuit is used to test said line as a calledline.

18. A telephone system including telephone lines, a plurality of linkcircuits for interconnecting said lines, an operators telephone and apair of relays common to said link circuits, a tone test device, andmeans controlled by said relays for operatively connecting said tonetest device to said operators telephone when the called line tested isalso the calling line.

19. A telephone system including a poly station subscribers telephoneline, an oper ators link circuit provided with only four relays for usein extending a call from said telephone line, an operators telephone,contacts controlled by two of said relays for automatically connectingand disconnecting said link circuit and said operators telephone, a tonetest device, and means inclividual to said operators telephone for usein operatively connecting said tone test device to said operatorstelephone when the operator tests a multiple jack of said telephone lineas the called line, said means including a relay normally connected tosaid operators telephone.

:20. A telephone system including telephone lines, a plurality of linkcircuits for interconnecting said lines, each of said link 0' ,cuitsbeing provided with only four relays, an operators telephone, mechanismineluding part of said relays for automatically connectinganddisconnecting said operators telephone and said link circuits, a tonetest device, and means common to said link circuits and individual tosaid operators telephone for operatively connecting said tone test device to said operators telephone when the called line tested is also thecalling line, said means including a relay normally connected to saidoperators telephone.

21. In a telephone system, the combination of a multi-party line havinga plurality of jacks, multiple conductors connecting said jacks,supervisory signals associated with said conductors, reverting testingmeans, controlling means therefor and a shunt of said controlling meansmaintained closed during the operation of the reverting testing means,said shunt including one of said multiple conductors.

22. In a telephone system, the combination of a multiparty telephoneline having a plurality of terminals, a cord circuit, supervisorysignals in said cord circuit, means for connecting the cord to theterminals, reverting testing means associated with said cord circuit,controlling means for said reverting testing means and a shunt 01?; saidcontrolling means controlled through the terminals of the multi-partyline, maintained closed during the sending of the reverting busy testsignals.

23. In a telephone system, the combination of a multi-party telephoneline terminating in multiple jacks, a cord circuit including talkingstrands and means for connecting said strands to telephone jacks,supervisory signals associated With said cord,

reverting testing apparatus associated Withthe cord circuit, controllingmeans therefor, and a shunt for said controlling means, including aportion of one of the talking strands of the cord circuit.

Signed by me at Chicago, county of Cook, and State of Illinois, in thepresence of two M. R. RooHFoRD.

